As known, in motor vehicles, the radiator is arranged in a front area of the engine compartment and is supported by a metal frame comprising an upper horizontal crosspiece, to which the bonnet is releasably coupled in order to close the engine compartment from above.
In the event of a frontal collision with pedestrian, the pedestrian's pelvis is struck by a front part of the bonnet, the deformation of which is limited by the presence of the aforementioned crosspiece underneath.
In order to absorb the impact and minimize injury to the pedestrian, safety systems introduced in the engine compartment are known. With regard to the safety of the area of the pedestrian's pelvis, active safety systems are normally used, such as air bags or actuators to move the bonnet or other members of the engine compartment, which are activated by an electronic control unit in response to signals emitted from suitable sensors.
However, in order to minimize costs, number components and weight of the motor vehicle, the need is felt to use passive safety systems, i.e. systems which may collapse when impacting, but which are equally effective.
The US patent application published with number U.S.2004/0188155A1 corresponds to the preamble of claim 1 and discloses a passive safety system, in which the radiator is supported from above by a crosspiece which may move backwards in the event of an accident, due to two plastically deformable, lateral portions which define a virtual hinge. The backward movement of the crosspiece allows to have more space available for the deformation of the bonnet. The need is felt to enhance this solution in order to obtain greater absorption of impact energy when colliding with a pedestrian.